Photographic element with polyesters blended with poly(ether imide)

ABSTRACT

A method for blending poly(ether imide)s with polyesters comprising: (a) adding polyester monomers and poly(ether imide) in a polymerization reactor at any point during a polyester polymerization process; and (b) polymerizing the polyester monomers in the presence of the poly(ether imide) under standard conditions to produce a blend.

FIELD OF THE INVENTION

[0001] This invention relates to a general method for preparinghomogeneous blends of poly(ethylene naphthalate) and other polyesterswith poly(ether imide)s.

BACKGROUND OF THE INVENTION

[0002] A novel blend of poly(ethylene naphthalate) (PEN) with poly(etherimide) (PEI) was disclosed in U.S. Pat. No. 5,599,658 as a resinformulation with a number of useful properties which makes it especiallyadvantageous for use in photographic film. In particular, a filmmanufactured from this blend at a certain composition range generallyretains the desirable properties of PEN film, while having a lowerpropensity to take up core-set curl. This property permits its use insmall diameter cartridges—for example, diameters in the range of 3-12.5mm—without suffering the consequence of an increased curl in the woundfilm. It is also possible to use less extreme annealing conditions(lower annealing temperature and/or shorter annealing time) with a filmcomprising the said blend formulation to achieve equivalent core-setpropensity to that of PEN film.

[0003] However, preparation of the blend formulation in accordance withU.S. Pat. No. 5,599,658, the contents of which are incorporated hereinin their entirety, requires thorough drying of all components and anadditional compounding step using, typically, a twin-screw extruder orequivalent melt compounding equipment. These additional steps raise thecost of the blend and make it less attractive economically compared tothe unblended PEN resin. In addition, the need to heat the resincomponents to high temperature during compounding can lead to thermaland hydrolytic degradation as well as contamination of the blended resinwith debris from the compounding equipment.

[0004] What is needed in the art is a method of preparing a blend ofpoly(ether imide) (PEI) with poly(ethylene naphthalate) (PEN),poly(ethylene terephthalate) (PET) and other polyesters that overcomesthe problems noted above.

SUMMARY OF THE INVENTION

[0005] The present invention discloses an in-situ process of blendingPEI and polyesters that provides better control of the blended polymerviscosity and avoids problems heretofore encountered in the blendingprocess.

[0006] The conventional, high temperature compounding step can beeliminated by adding the PEI resin directly into the reactor used forpreparing the PEN polymer. The invention discloses that, contrary toexpectation, the presence of PEI pellets in the polyester polymerizationreaction vessel has no adverse effect on the kinetics and extent of thepolymerization reaction and allows easy blending and homogenizing of theadded PEI resin with the polymerizing PEN species. The final resinobtained by this “in-situ” blending process is a homogeneously dispersedPEN/PEI blend with a sufficiently high inherent viscosity (IV) and asingle glass transition temperature (Tg).

DETAILED DESCRIPTION OF THE INVENTION

[0007] Poly(ethylene naphthalene), sometimes abbreviated as PEN,previously has been used as a support for magnetic recording andplayback tapes and had been proposed for use as a support forphotographic film, for example in U.S. Pat. No. 4,141,735, U.S. Pat. No.5,294,473 and U.S. Pat. No. 5,368,997. The '473 and '997 patents broadlydescribe copolyesters with PEN and blends of PEN with other polymers,but not with a poly(ether imide). The PEN used in the polymer blend ofthis invention can be the same polymer as described in this prior art,such as U.S. Pat. No. 5,368,997, the disclosure of which is incorporatedherein by reference. Preferably it is PEN, particularlypoly(ethylene-2,6-naphthalate).

[0008] The PEN used in the polymer blends of this invention preferablyhas molecular weights represented by inherent viscosities in the rangeof 0.5 to 0.9 dl/g. (Inherent viscosity is measured in a Ubbelhodecapillary viscometer (Shott Gerate 536-13) at 25° C. and at a polymerconcentration of 0.25 g/dL in a 50/50 mixture by weight ofpentafluorophenol and 1,2,4-trichlorobenzene.) The PEN used in thepolymer blends of this invention preferably has a glass transitiontemperature (Tg), above about 118° C.

[0009] Poly(ether imide), sometimes abbreviated as PEI, is thecondensation product of a bis(etherdianhydride) and an organic diamine.Its synthesis, structure and use are described in U.S. Pat. Nos.3,803,085, 3,847,867, 3,905,942, 4,011,198 and 4,293,684. The particularPEI used in the polymer blends of this invention can be as described inthis prior art, such as U.S. Pat. No. 3,847,867, the disclosure of whichis incorporated herein by reference. A preferred PEI is one in which thebis(etherdianhydride) is 2,2-bis[4-(2,3-dicarboxyphenoxy)phenyl]propanedianhydride (also known as Bisphenol A dianhydride) and the organicdiamine is m-phenylene diamine.

[0010] Preferably, the PEI has a molecular weight represented by a meltviscosity in the range of 10³ to 10⁵ poise. Melt viscosity is measuredaccording to the following procedure: A sample of the PEI in pellet formis dried under vacuum at 150° C. for 10 hrs. The dried sample is loadedinto a parallel disk (25 mm diameter) fixture of a Rheometrics SystemIV® rheometer (manufactured by Rheometrics, Inc., Possumtown Rd.,Piscataway, N.J. 08854) and its temperature is raised to 305° C. Theviscosity of the melt is determined by shearing the resin at a constantoscillating frequency of 1 rad/s.

[0011] The PEI used in this invention preferably has a glass transitiontemperature (Tg) which is above 150° C. In addition, the PEI should bemiscible with the PEN. By miscible is meant that the blend of the twopolymers has a single glass transition temperature (Tg) and that aphotographic film base made from the blend is clear. The PEI isavailable commercially from the General Electric Company, One PlasticsAve., Pittsfield, Mass. 01201, under the Ultem® trade name.Representative grades are Ultem 1000® and Ultem 1010®.

[0012] Blending of PEI with polyesters, such as PET and PEN is broadlydescribed in U.S. Pat. No. 4,141,927 and Research Disclosure, November1987, Item 28338, pages 677-8. (Research Disclosure is published byKenneth Mason Publications, Ltd., Dudley Annex, 12a North Street,Emsworth, Hampshire P010 7DQ, ENGLAND.) These patents and publication donot describe the blends of this invention or suggest that they would besuitable for use as a photographic film base. Nor does any of this artsuggest that blending PEI with PEN would have any influence on thecore-set and post-process curl characteristics of a film based preparedfrom the blend, let alone suggest that such a blend would provide a filmbase in which these characteristics were improved.

[0013] The blends of this invention preferably have the followingphysical characteristics: a Tg of greater than 125° C.; a tensilemodulus greater than 350 Kg/mm²; light transmission greater than 80%;and haze less than 3%. The way in which these characteristics aredetermined is described in the Examples in U.S. Pat. No. 5,599,658.

[0014] While the relative proportions of PEN and PEI may vary somewhatwith variations in the particular PEI employed, as well as with thepresence of other components in the blend, preferred proportions of PENand PEI in the blends of this invention are from 70 to 95 weight percentPEN and from 5 to 30 weight percent of PEI. When the proportion of PEIis increased, we have found that the tensile modulus is decreased, thecrystallinity of the blend is lowered and a sheet formed from the blendbecomes difficult to stretch. When the proportion of PEI is decreasedbelow the said range, we have found that the improvement in physicalperformance of the blend becomes insignificant. Preferably theproportion of PEI is between 10 and 20 percent by weight. Mostpreferably the proportion of PEI is between 12 and 17 percent by weight.These are the preferred proportions for PEI prepared from bisphenol Adianhydride and m-phenylene diamine.

[0015] Film base is prepared from the polymer blend by techniques knownto those skilled in the art. These techniques are described in detail inSchrader U.S. Pat. No. 4,141,735, the disclosure of which isincorporated herein by reference. A film base is understood to be aplanar sheet having a thickness in the range of 50 to 200 μm, preferablya thickness of 70 to 110 μm.

[0016] In a typical operation, the film base is formed by extruding thepolymer blend at a temperature of 290 to 320° C. through a sheeting dieand casting the molten sheet on a chill roll at a temperature of 60 to120° C. The cast sheet is then stretched biaxially to from 2 to 5 timesits initial lateral dimensions. Stretching can be at a temperature inthe range of from 130 to 170° C. Biaxial stretching can be sequential orsimultaneous. After stretching the film base is heatset at a temperaturein the range of 200 to 250° C. for time in the range of 0.1 to 10 sec.If the film base is to be annealed, it can be annealed at a temperaturein the range of from 50° C. up to the Tg of the polymer blend for a timein the range of 0.1 to 1000 hours. Film base with core-setcharacteristics useful for small diameter film cartridges can beobtained with preferred blends of this invention by annealing attemperatures of between about 90 and 125° C. for times of 6 to 72 hrs.

[0017] Film base prepared from polymer blends of this invention cancontain other components commonly found in film supports forphotographic elements. These include dyes, lubricants and particles oforganic and inorganic materials such as glass beads. These are describedin more detail in Research Disclosure, February 1995, Item 37038, pages79-114.

[0018] Film base prepared from polymer blends of this invention can bearlayers commonly found on film supports used for photographic elements.These include magnetic recording layers, subbing layers between otherlayers and the support, photosensitive layers, interlayers and overcoatlayers, as are commonly found in photographic elements. These layers canbe applied by techniques known in the art and described in thereferences cited in Research Disclosure Item 37038 cited above.

[0019] Magnetic recording layers that can be used in photographicelements of this invention are described in U.S. Pat. Nos. 3,782,947;4,279,945; 5,147,768; 5,252,441; 5,254,449; 5,395,743; 5,397,826;5,413,902; 5,427,900, 5,432,050, 5,434,037, 5,436,120, in ResearchDisclosure November 1992, Item 34390, pages 869 et seq.

[0020] Photographic elements of this invention can have the structuresand components shown on Research Disclosure 37038 cited above and can beimagewise exposed and processed using known techniques and compositions,including those described in the Research Disclosure Item 37038 citedabove.

[0021] Blending of PEI with polyesters, such as PET and PEN, is broadlydescribed in U.S. Pat. No. 4,141,927 and Research Disclosure, November1987, Item 28338, pages 677-8 (Research Disclosure is published byKenneth Mason Publications, Ltd., Dudley Annex, 12a North Street,Emsworth, Hampshire P010 7DQ, UK). Both of these publications citeexamples of a melt or a solution blending process for the PEI andpolyester components. However, they do not describe nor do they suggestthe possibility of an “in-situ” blending process such as is claimed inthe present invention. In-situ blending has been applied in previousinventions to the preparation of blends of mostly addition-typepolymers, e.g., various polyolefins (U.S. Pat. Nos. 5,225,457;5,126,398; 5,149,738; 5,047,468; 5,677,375 and 4,522,962) and styrenics(E.P. No. 135,168). The polymers of the present invention, polyesters,are produced by a condensation-type polymerization process, which isfundamentally different from the addition process used for preparingpolyolefins and styrenics or from the condensation process of otherpolymers. The general procedure of the polyester polymerization processis well known to those skilled in the art. Suitable polyesters for thisinvention are any that are manufactured by a polycondensation process attemperatures greater than the glass transition temperature of thepoly(ether imide). Some examples of such polyesters and copolyestersinclude polycondensation products of diacid (or diester analogs) andglycols such as terephthalic acid, naphthoic acid,5-sodiosulfoisophthalic acid, isophthalic acid, ethlylene glycol,diethylene glycol, poly(ethylene glycol), poly(propylene glycol),cyclohexane dimethanol, butanediol, neopentyl glycol, trimethylolpropane and pentaerythritol. The weight ratio of polyester:poly(etherimide) in the blend is 95:5 to 70:30, preferably 80:20 to 90:10. Thepoly(ether imide) may be added to a continuous polymerization reactor ora batch polymerization reactor. In one embodiment of the invention thepolyester is poly(ethylene-2,6-naphthalate). In another embodiment thepoly(ether imide) is a condensation polymer of2,2-bis[4-(2,3-dicarboxyphenoxy)phenyl]propane dianhydride andm-phenylene diamine. The weight ratio ofpoly(ethylene-2,6-naphthalate):the condensation polymer of2,2-bis[4-(2,3-dicarboxyphenoxy)phenyl]propane dianhydride andm-phenylene diamine in the blend is 80:20 to 90:10.

[0022] In yet another embodiment, the polyester is poly(ethyleneterephthalate). The weight ratio of poly(ethyleneterephthalate):poly(ether imide) in the blend is 95:5 to 70:30. Apreferred poly(ether imide) is the condensation polymer of2,2-bis[4-(2,3-dicarboxyphenoxy)phenyl]propane dianhydride andm-phenylene diamine. The weight ratio of poly(ethyleneterephthalate):the condensation polymer of2,2-bis[4-(2,3-dicarboxyphenoxy)phenyl]propane dianhydride andm-phenylene diamine in the blend is 95:5 to 70:30, preferably 80:20 to90:10.

[0023] The method of the invention is useful to prepare a blend for filmsupports in photographic elements. An exemplary photographic element maycomprise a film support bearing at least one photographic layer, thefilm support comprising a homogenous blend of from 70 to 95 weightpercent poly(ethylene naphthalate) and from 30 to 5 weight percent of apoly(ether imide), preferably 80 to 90 weight percent poly(ethylenenaphthalate) and from 20 to 10 weight percent of a poly(ether imide).

[0024] The following examples further illustrate this invention.

EXAMPLE 1

[0025] 15% PEI in PEN using in-situ blending

[0026] 100.778 g of 2,6-dimethyl naphthalene dicarboxylate is added to a500 ml, 3 neck, round bottom flask. 51.220 g ethylene glycol, 0.025 gmanganese acetate dihydrate and 0.027 g antimony trioxide are also addedto the flask. The flask is fitted with a stirrer, distillation head andcondenser. The flask is immersed in a 190° C. bath. The bath temperatureis held at 190° C. for 1 hour and then ramped to 250° C. at 0.4° C./min.Methanol begins to distill over after the flask has been in the bath forabout 17 minutes. The 26.4 g theoretical amount of methanol is removedby the time the bath temperature reaches 250° C. The mixture is held inthe 250° C. bath for 1 hour. 17.6 g of Ultem 1000® poly(ether imide)(PEI) which has been dried for 24 hours in a 150° C., 20 mm Hg vacuumoven is added to the mixture in the flask. Some foaming is seen asresidual moisture in the PEI boils off. About 7 minutes after the PEIaddition a ramp is begun to 310° C. at 1° C./min. At a bath temperatureof 260° C., the distillation head is removed and a sidearm to vacuum isinstalled on the flask. Vacuum is applied from a water aspirator for 10minutes. Then mechanical pump vacuum to 1 mm Hg is applied. After 45minutes on pump vacuum, the vacuum is relieved with nitrogen. The 15weight percent PEI in PEN mixture has a PEN equivalent weight averagemolecular weight in 20:80::dichloroacetic acid:dichloromethane of 41,100and an inherent viscosity in 50:50::pentafluorophenol:trichlorobenzeneof 0.668 dl/g. The second heat of differential scanning calorimetry at10° C./min shows a single Tg of 129° C., a single onset ofcrystallization of 214° C. and a single onset of melting of 251° C.Another laboratory synthesis yielded a single Tg of 133° C., a singleonset of crystallization of 222° C. and an onset of melting of 258° C.The Tg of Ultem 1000® is about 217° C., and the Tg of PEN is about 120°C.

EXAMPLE 2 (Comparative)

[0027] 15% PEI in PEN blended in a twin screw extruder. PEN and Ultem1000® pellets are blended in a twin screw extruder and pelletized. Thesecond heat of differential scanning calorimetry at 10° C./min shows asingle Tg of 131° C., a single onset of crystallization of 214° C. and asingle onset of melting of 254° C.

EXAMPLE 3

[0028] 15% PEI in PET using in-situ blending

[0029] 85.832 g dimethyl terephthalate is added to a 500 ml, 3 neck,round bottom flask. 49.383 g ethylene glycol, 0.022 g zinc acetatedihydrate and 0.034 g antimony trioxide are also added to the flask. Theflask is fitted with a stirrer, distillation head and condenser. Theflask is immersed in a 190° C. bath. The bath temperature is held at190° C. for 2 hours and then ramped to 250° C. at 0.83° C./min. Methanolbegins to distill over after the flask has been in the bath for about 9minutes. The 28.3 g theoretical amount of methanol is removed by thetime the bath temperature reaches 250° C. The mixture is held in the250° C. bath for 1 hour. 15 g of Ultem 1000® poly(ether imide) (PEI)which has been dried for 24 hours in a 150° C., 20 mm Hg vacuum oven isadded to the mixture in the flask. Some foaming is seen as residualmoisture in the PEI boils off. About 7 minutes after the PEI addition aramp is begun to 295° C. at 1.5° C./min. At a bath temperature of 260°C., the distillation head is removed and a sidearm to vacuum isinstalled on the flask. Vacuum is applied from a water aspirator for 10minutes. Then mechanical pump vacuum to 1 mm Hg is applied. After 36minutes on pump vacuum, the vacuum is relieved with nitrogen. The 15weight percent PEI in PET mixture has a PET equivalent weight averagemolecular weight in 20:80::dichloroacetic acid:dichloromethane of 38,100and an inherent viscosity in 60:40::phenol:chlorobenzene of 0.598 dl/g.The second heat of differential scanning calorimetry at 10° C./min showsa single Tg of 89° C., a single onset of crystallization of 162° C. anda single onset of melting of 238° C. The Tg of PET is about 76° C.

[0030] The invention has been described in detail with particularreference to certain preferred embodiments thereof, but it will beunderstood that variations and modifications can be effected within thespirit and scope of the invention.

What is claimed is:
 1. A method for blending poly(ether imide)s withpolyesters comprising: (a) adding polyester monomers and poly(etherimide) in a polymerization reactor at any point during a polyesterpolymerization process; and (b) polymerizing the polyester monomers inthe presence of the poly(ether imide) under standard conditions toproduce a blend.
 2. The method of claim 1 wherein the weight ratio ofpolyester:poly(ether imide) in the blend is 95:5 to 70:30.
 3. The methodof claim 1 wherein the weight ratio of polyester:poly(ether imide) inthe blend is 80:20 to 90:10.
 4. The method of claim 1 wherein thepoly(ether imide) is added to a continuous polymerization reactor or abatch polymerization reactor.
 5. The method of claim 1 wherein thepolyester is poly(ethylene2,6-naphthalate).
 6. The method of claim 1wherein the poly(ether imide) is a condensation polymer of2,2-bis[4-(2,3-dicarboxyphenoxy)phenyl]propane dianhydride andm-phenylene diamine.
 7. The method of claim 5 wherein the weight ratioof poly(ethylene naphthalate):poly(ether imide) in the blend is 95:5 to70:30.
 8. The method of claim 5 wherein the weight ratio ofpoly(ethylene naphthalate):poly(ether imide) in the blend is 80:20 to90:10.
 9. The method of claim 5 wherein the weight ratio ofpoly(ethylene-2,6-naphthalate):the condensation polymer of2,2-bis[4-(2,3-dicarboxyphenoxy)phenyl]propane dianhydride andm-phenylene diamine in the blend is 80:20 to 90:10.
 10. The method ofclaim 9 wherein the weight ratio of poly(ethylene-2,6-naphthalate):thecondensation polymer of 2,2-bis[4-(2,3-dicarboxyphenoxy)phenyl]propanedianhydride and m-phenylene diamine in the blend is 95:5 to 70:30. 11.The method of claim 1 wherein the polyester is poly(ethyleneterephthalate).
 12. The method of claim 11 wherein the weight ratio ofpoly(ethylene terephthalate):poly(ether imide) in the blend is 95:5 to70:30.
 13. The method of claim 11 wherein the weight ratio of ispoly(ethylene terephthalate):poly(ether imide) in the blend is 80:20 to90:10.
 14. The method of claim 11 wherein the poly(ether imide) is acondensation polymer of 2,2-bis[4-(2,3-dicarboxyphenoxy)phenyl]propanedianhydride and m-phenylene diamine.
 15. The method of claim 11 whereinthe weight ratio of poly(ethylene terephthalate):the condensationpolymer of 2,2-bis[4-(2,3-dicarboxyphenoxy)phenyl]propane dianhydrideand m-phenylene diamine in the blend is 95:5 to 70:30.
 16. The method ofclaim 1 wherein the polyester or copolyester is selected from the groupconsisting of polycondensation products of diacids, diester analogs andglycols.
 17. The method of claim 16 wherein the diacid is terephthalicacid, naphthoic acid, 5-sodiosulfoisophthalic acid, or isophthalic acidor their diester analogs.
 18. The method of claim 16 wherein the glycolis ethlylene glycol, diethylene glycol, poly(ethylene glycol),poly(propylene glycol), cyclohexane dimethanol, butanediol, neopentylglycol, trimethylolpropane or pentaerythritol.
 19. A photographicelement comprising a film support bearing at least one photographiclayer, the film support comprising a homogenous blend of from 70 to 95weight percent poly(ethylene naphthalate) and from 30 to 5 weightpercent of a poly(ether imide).
 20. A photographic element comprising afilm base bearing at least one photographic layer, the film basecomprising a homogenous blend of from 80 to 90 weight percentpoly(ethylene naphthalate) and from 20 to 10 weight percent of apoly(ether imide).